Downton Abbey love story is such a laugh

'Special bond': Joanne Froggatt and Brendan Coyle in a scene from Downton

The simmering love story of Downton Abbey's valet John Bates and head housemaid Anna Smith has gripped millions.

And while revealing nothing of the on/off relationship in the new series of the ITV drama, actors Joanne Froggatt and Brendan Coyle have told how they have such fun doing the scenes that they "feel guilty".

Froggatt admitted they often collapse in fits of giggles during filming, adding: "We can't believe we're getting paid to do this."

Froggatt, 31, said of her co-star: "We've become really good mates. We genuinely get on really well.

"It's so nice to come back for a second series and already have a friendship and be able to slip into the scene." Coyle said they had a special bond like their characters. He added: "We have a shorthand now, a sort of understanding of each other."

Following the success of Downton Abbey at the Emmys, the pair are contemplating careers in America. Coyle, 47, said: "The feedback has been amazing, so we'll see."